Nozzle for sand and shot blasting



pi- H. L. GRISWOLD 2,428,276

NOZZLE FOR SAND AND SHOT BLASTING Filed- June 28, 1945 ,h'owako L. GE/SWOL D Wm U A TTdEKrE y.

Patented Sept. 30, 1947 NQZ LE EOE SAND I? SHQ AS TI G lioward L. Griswold, Canton, Ohio, assignor to Coast Metals, Inc., Canton,

of Delaware Qhio, a eorp'oration Appli ation June 194s Scr alhlm 22 003. 7

4 Claims.

This invention relates, as indicated, to nozzles for sand and shot blasting,

In angled nozzles of the conventional type, which are used in sand and shot blasting equipment to clean the inside of pipe and shells, cored holes in castings, and other places to which access is difficult, as well as for cleaning the sides of buildings where steam and air hoses must be placed in vertical positions, and for many other purposes, the center line or axis of the bore follows closely the center line or axis of the nozzle. With this arrangement or location of the bore, the angle at deviation which is taken by the particles of sand or shot in their passage through the bore is so large, that the resulting abrasive effect of such particles on the inside of the nozzle reduces the life of the nozzle to a few hours, in most cases.

The present invention, accordingly, has as its primary object the provision of nozzles of the type described, but modified in design to materially increase the wearing or useful life of the nozzle.

Another object of the invention is to provide a nozzle having a wearing area or zone of a thickness materially greater than is found in conventional nozzles.

A further object of the invention is to provide a nozzle of the character described having a bore, the center line or axis of which is eccentric to the center line or axis of the nozzle, whereby the angle of deviation referred to above is decreased and the life of the nozzle greatly increased.

A further object of the invention is to provide a nozzle of the character described, having a bore, the center line or axis of which is eccentric to the center line or axis of the nozzle, whereby the maximum wearing distance along the nozzle is increased and the life of the nozzle thereby greatly increased.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

' Fig. 1 is an elevation of the inlet end of a conventional type of nozzle employed for sand and shot blasting;

Fig. 2 is a cross-sectional view, taken on the line 22 of Fi 1;

Fig. 3 is an elevation of the outlet end of the nozzle;

Fig. 4 is a view similar to Fig. 1, but of a nozzle 2 const uct d accordance wit he e en inven n;

F st 5 is a crosscti n l ew. taken on the line 5- on Fig, 6 is an elevation of, the outlet end of the nozzle shown in Figs. 4 and 5.

Referring to Figs. 1 to 3 of the drawing, it will be seen that a conventional type of nozzle employed for sand and shot blasting comprises a generally straight portion 1 and an arcuate or curved portion 2, which extends from the curved portion, and the center of which is indicated at El. The nozzle is of icircular transverse cross-section, and is provided with a tapered inlet opening 3 at one end of the portion I, which communicates with a passageway or bore 5 of circular crosssection. The portion of the bore 5 which extends through the portion l of the nozzle is straight and concentric with the portion l, but that portion thereof, which extends through the portion 2 of the nozzle is curved, so that its axis or center line, designated XX, substantially coincides with the axis or center line of the portion 2.

In such a nozzle, it may be assumed that a particle which enters the nozzle, and the path of which is indicated by the arrows, will strike the wall of the bore 5 and will bounce off such wall at approximately the same angle at which it struck the Wall. The angle of deviation, in such case, which is'reapresented as the angle between a line which is an extension of the line taken by the impinging particle, and the line taken by the particle after it impinges against the wall of the bore, is relatively large. The maximum wearing distance, in such case, which is represented at the thickness of the wall of the nozzle in a direction along the line taken by the impinging particle, is, on the other hand, relatively small.

Due to such large angle of deviation, the abrasive effect of the particles on the inside of the nozzle is such that the life of the nozzle is seldom more than a few hours, and such nozzles, accordingly, have to be frequently replaced.

Referring now to Figs. 4, 5 and 6 of the drawings, the nozzle therein shown has substantially the same external contour or form as the nozzle shown in Figs. 1, 2 and 3, and has substantially the same tapered inlet opening 3. In this case, however, the bore or passageway 5, which extends from the opening 3' to the outlet curve of the nozzle has its center line or axis X-X' displaced from or eccentric with respect to the center line or axis XX of the nozzle.

The displacement of the bore 5' may be obtained by using a spiralized curve for the core, although a similar result would be obtained by using a circular arc of a greater radius than that of the nozzle, a section of a parabola, an involute curve, an ellipse, or even a combination of arcs and tangents. In the nozzle shown in Fig. 5, the central portion of the bore 5 is in the form of an are described about the center 0', such are being of considerably larger radius than that of the external surface of the nozzle, which is in the form of an arc drawn about the center 0.

The effect of displacing the bore 5' from the center line or axis of the nozzle is to reduce the angle of deviation, as well as to increase the maximum wearing distance, each of which efiects can be readily observed in Fig. 5. By thus in creasing the angle of deviation and increasing the maximum wearing distance, the life of the nozzle is materially increased.

It is to be understood that the forms of my invention, herewith shown and described, are to be taken as preferred examples of the same, and

that various changes in th shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. A curved sand or shot blast nozzle having a curved bore extending therethrough, the radius of curvature of the bore being greater than the radius of curvature of th nozzle, and the center of curvature of the bore being displaced toward the inlet end of the nozzle relative to the center of curvature of the nozzle, and the bore at its inlet end being concentric relative to the axis or the nozzle.

2. A nozzle, as defined in claim 1, in which the bore at its outlet end is eccentric relative to the axis of the nozzle.

3. A curved sand or shot blast nozzle having a curved bore extending therethrough, the major portion of the bore having a radius of curvature which is greater than the radius of curvature of the nozzle, and the center of curvature of said portion of the bore being displaced toward the inlet end of the nozzle relative to the center of curvature of the nozzle, and the bore at its inlet end being concentric relative to the axis of the nozzle.

4. A nozzle, as defined in claim 3, in which the bore at its outlet end is eccentric relative to the axis of the nozzle.

HOWARD L. GRISWOLD.

REFERENCES CITED The following references are of record in the file of this patent: 

